Field of the Invention
The present invention relates to friction-reducing and/or wear-reducing modifiers and, more particularly, to a combination of aqueous salt solutions and moderately hydrophilic single phase compounds that singly or together create emulsions within base lubricating fluids, thereby increasing the anti-friction and/or anti-wear properties of those base lubricating fluids.
Technical Background
Some of the energy used to operate industrial equipment is devoted to overcoming internal friction and wear. Base lubricants typically are used to reduce friction and wear. Whether conventional or synthetic, these base lubricants may be enriched with friction modifiers, wear modifiers, and detergent packages. Several different friction and wear modifiers and detergent packages are currently used in motor oils, especially, and are miscible with the base lubricant. These friction and wear modifiers modify sliding and rolling friction within boundary lubrication layers between surfaces, usually metallic surfaces. For sliding surfaces this boundary layer typically is found to be a hydrodynamic boundary layer; for high-speed ball bearings this boundary layer is often found to be the elastohydrodynamic boundary layer. When lubricant base is changed out, friction and wear modifiers and detergent packages are removed as well.
Lubricants act at the boundary between two surfaces and form a layer that keeps the two surfaces apart. When the lubricant can no longer maintain separation at the boundary layer, the surfaces come into contact and relatively rapid wear and failure occurs. Lubricants have limited use in reducing friction and wear since their operational limits of performance at boundary layers are always defined; however, those limits of performance are also subject to improvements. Conversion coatings can create relatively long-lasting boundary layers and can be more effective in reducing friction. A conversion coating consisting mainly of metal may reduce friction effectively at a surface. Defalco and McCoy (U.S. Pat. No. 5,540,788) demonstrated that molybdenum, zinc, or tungsten can be deposited as a conversion coating on an iron surface when the salts of these metals are first dissolved in an inorganic phosphate polymeric water complex and then delivered in an oil lubricant vehicle to the iron surface. The polymeric water complex by itself forms a phosphate and potassium conversion surface on an iron surface when delivered in the lubricant vehicle. The phosphate/potassium conversion coating by itself significantly improved the friction reducing properties of the lubricant vehicle. Adding molybdenum, zinc, or tungsten to the polymeric water complex did not produce an improved anti-friction effect compared to the polymeric water complex alone.
Defalco (US Patent Application No. 2008/0302267) disclosed a formulation for aqueous solutions of metal ions that can form conversion coatings on any metal surface without the use of external electromotive force. The metal ionic solutions produce anti-friction protection similar to standard lubricating oil. Although Defalco's inorganic aqueous ionic solutions can be formulated to create non-alkaline metal conversion coatings on metals, they do not appear to offer an advantage over standard liquid or dry organic lubricating agents for reducing friction. It is expected that these metal ionic solutions can be added to lubricating oils containing complex emulsifying detergents and/or dispersants, such as those contained in motor oils, and they may increase the anti-friction properties of the motor oil. However, many non-motor oil lubricants, henceforth termed gear oils, compressor oils, extruder oils, hydraulic oils, water, antifreeze, and the like do not contain the complex of emulsifying detergents and/or dispersants that are present in motor oils. It has been unknown heretofore how to produce emulsions in non-motor oil lubricants whereby those emulsions have affinity for associating with boundaries, thereby providing boundary layer organization-enhancing anti-friction and/or anti-wear properties of the base lubricants.